D1.2 Protein Synthesis

Question 1

transcription definition

Answer 1

synthesis of messenger RNA using a DNA template

Question 2

what is rna polymerase

Answer 2

enzyme that catalyses the synthesis of RNA molecules from a DNA template

Question 3

where does transcription occur

Answer 3

cytoplasm for prokaryotes
nucleus in eukaryotes

Question 4

process of transcription simple

Answer 4

part of dna unwinds because hydrogen bonds between complementary base pairs break

complementary copy of code from gene is made by building mRNA

RNA nucleotides pair up with complementary bases on unzipped DNA molecule

double stranded dna re-formed when hydrogen bonds between mRNA and DNA strands break

Question 5

coding strand `

Answer 5

strand of dna that carries the genetic code

not used as template during replication

Question 6

template strand

Answer 6

opposite dna strand which doesnt carry genetic code

used during transcription to produce mRNA

complementary to coding strand of DNA

Question 7

role of hydrogen bonds in transcription

Answer 7

broken in dna to unzip it
formed between mRNA strand and DNA strand for complementary base pairing

Question 8

which strand is transcribed to form MRNA molecule

Answer 8

template strand

to get an rna transcript of coding strand

Question 9

why is dna is a very stable molecule

Answer 9

due to hydrogen bonding between the DNA bases of the 2 strands and the strong phosphodiester bonds between adjacent nucleotides in each strand

Question 10

what does sugar phosphate backbone ensure

Answer 10

ensures stability of base sequence

Question 11

why is stability important

Answer 11

so that genetic code is not prone to spontaneously breaking or changing

allows dna to act as reliable templates for transcription

Question 12

gene expression

Answer 12

the process by which the information encoded in a gene is used to direct the synthesis of a protein molecule

Question 13

what to specialised cells do to match requirements of cell

Answer 13

switch them on or off

Question 14

which genes get switched on

Answer 14

genes that are expressed and undergo transcription and translation

Question 15

which genes get switched off or silenced

Answer 15

genes that are not expressed and do not go through transcription or translation

Question 16

translation definition

Answer 16

the information. of mRNA is decoded into proteins

involves taking the genetic code from the mRNA and synthesising a polypeptide

Question 17

where does translation occur

Answer 17

in the cytoplasm

Question 18

when does translation occur

Answer 18

after transcription as the mRNA template comes from transcription

Question 19

what are the parts of a ribosome

Answer 19

2 - big and small

Question 20

what are ribosomes made of

Answer 20

protein and rRNA
ribosomal rna

Question 21

where in a ribosome does mRNA bind to

Answer 21

small subunit

Question 22

where in a ribosome does tRNA bind to

Answer 22

2 of them bind simultaneously to the large subunit

Question 23

what does complementary base pairing in translation happen between

Answer 23

codons and anticodons

Question 24

triplet

Answer 24

a sequence of 3 DNA bases that codes for a specific amino acid

Question 25

codon

Answer 25

a sequence of 3 mRNA bases that codes for a specific amino acid

Question 26

what is codon complementary to

Answer 26

triplet

Question 26

Anticodon

Answer 26

a sequence of 3 tRNA bases that are complementary to a codon

Question 27

what does tRNA carry

Answer 27

the appropriate amino acid to the ribosome

Question 28

what commands to codons carry

Answer 28

start and stop to start and stop translation when the polypeptide chain is complete

Question 29

what are the stop codons

Answer 29

UAA UAG UGA

Question 30

sites of an amino acid

Answer 30

A - aminoacyl P - pepticyle E - exit site

Question 31

how many amines are there to be coded for

Answer 31

20

Question 32

how many bases for one amino

Answer 32

3

Question 33

what translations 3 base sequence to an amino acid sequence

Answer 33

tRNA

Question 34

to what are the amino acids bonded

Answer 34

bonded covalently to the site at the bottom of tRNA only 1 particular amino can be bonded for one particular tRNA

Question 35

why are enzymes important in attaching amino to tRNA

Answer 35

enzymes are specific to amino acids which is a way of making sure that the correct amino acids are used in the right sequence

Question 36

how are amino acid completes held in position

Answer 36

temporarily held in position by hydrogen bonds

Question 37

the genetic code ideas

Answer 37

* common original of life on earth * process of reading the code and process of protein synthesis through use of ribosomes and RNA are very similar in prokaryotes and eukaryotes

Question 38

universality of genetic code

Answer 38

means that almost every organisms uses the same code genetic info is transferable between species reason why genetic engineering is possible

Question 39

result of start and stop codons

Answer 39

reads dna correctly and produces the correct sequences of amino acids that it requires to function properly

Question 40

how many codons possible

Answer 40

64 because 4 bases (ATCG) 4^3=64

Question 41

degenerate

Answer 41

multiple codons can be coded for the same amino acid

Question 42

why can codes be degenerate

Answer 42

because 20 amino acids but 64 codons possible can limit effect of mutation s

Question 43

how can the amino be read - table

Answer 43

first convert DNA to mRNA or any RNA check table from that and name it

Question 44

how is the polypeptide chain elongated

Answer 44

* during translation the ribosome moves in steps along mRNA * in each step the ribosomes moves 3 bases along the mRNA * repetition leads to a polypeptide being formed and elongated

Question 45

what are gene mutations

Answer 45

copying errors that take place when DNA is replicated during synthesis and interphase

Question 46

what mutations are not inherited

Answer 46

mutations preset in normal body cells are not inherited and eliminated when affected cells die

Question 47

what mutations are inherited

Answer 47

mutations within gametes are inherited by offspring

Question 48

point mutations

Answer 48

when one base in the DNA sequence is altered can result in changed amino acid at location

Question 49

examples of point mutation

Answer 49

sickle cell disease

Question 50

why is sickle cell disease caused

Answer 50

caused by a single point mutation within the gene that codes for alpha global peptide in haemoglobin most humans have the allele HbA mutation results in HbB

Question 51

effects of sickle cell disease

Answer 51

have limited oxygen carrying capacity blocks the capillaries and limit flow for normal RBCs